1. Field of the Invention
The present invention relates to an engine intake system.
2. Description of the Related Art
Known idle-speed control apparatuses control an idle speed of an engine to a target idle speed according to the conditions of the engine. For example, in the device disclosed in Japanese Patent Application Laid-Open Publication No. 9-42119, a base portion protrudes from a throttle body and an idle-speed control apparatus is mounted to the base portion. The base portion contains a water reservoir at a midpoint in a bypass passage from the idle-speed control apparatus to a bore in the throttle body so that drops of water from condensation in the throttle body and from air cleaner piping can be temporarily stored therein. In this way, it is possible to prevent water from blocking the bypass passage in order to reliably supply bypass air.
In the technique described above, however, the water reservoir is formed by partially extending the bypass passage. Because space for additionally forming the water reservoir is required, the bypass passage structure may increase in size. If special members for the water reservoir are provided, the number of parts increases and the intake system becomes complicated.